The primary objectives of this open label single arm noncomparative trial are to evaluate the safety and tolerability of 141W 94 in HIV-infected pediatric subjects (ages 4-18) for a minimum 48 week period and to determine the antiviral effect of 141W94 in combination with current antiretroviral therapy, based on plasma HIV RNA levels. The study is also designed to assess the pharmacokinetics of 141W94 in combination with two nucleoside reverse transcriptase inhibitors in HIV-1 infected children.